@article{UrlaubKaiserScherf‐Claveletal.2021, author = {Urlaub, Jonas and Kaiser, Reinhard P. and Scherf-Clavel, Oliver and Bolm, Carsten and Holzgrabe, Ulrike}, title = {Investigation of isomerization of dexibuprofen in a ball mill using chiral capillary electrophoresis}, series = {Electrophoresis}, volume = {42}, journal = {Electrophoresis}, number = {17-18}, doi = {10.1002/elps.202000307}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-225852}, pages = {1790 -- 1799}, year = {2021}, abstract = {Besides the racemate, the S-enantiomer of ibuprofen (Ibu) is used for the treatment of inflammation and pain. Since the configurational stability of S-Ibu in solid state is of interest, it was studied by means of ball milling experiments. For the evaluation of the enantiomeric composition, a chiral CE method was developed and validated according to the ICH guideline Q2(R1). The addition of Mg\(^{2+}\), Ca\(^{2+}\), or Zn\(^{2+}\) ions to the background electrolyte (BGE) was found to improve Ibu enantioresolution. Chiral separation of Ibu enantiomers was achieved on a 60.2 cm (50.0 cm effective length) x 75 μm fused-silica capillary using a background electrolyte (BGE) composed of 50 mM sodium acetate, 10 mM magnesium acetate tetrahydrate, and 35 mM heptakis-(2,3,6-tri-O-methyl)-β-cyclodextrin (TM-β-CD) as chiral selector. The quantification of R-Ibu in the mixture was performed using the normalization procedure. Linearity was evaluated in the range of 0.68-5.49\% R-Ibu (R\(^{2}\) = 0.999), recovery was found to range between 97 and 103\%, the RSD of intra- and interday precision below 2.5\%, and the limit of quantification for R- in S-Ibu was calculated to be 0.21\% (extrapolated) and 0.15\% (dilution of racemic ibuprofen), respectively. Isomerization of S-Ibu was observed under basic conditions by applying long milling times and high milling frequencies.}, language = {en} } @article{BrosgeLorenzHeltenetal.2019, author = {Brosge, Felix and Lorenz, Thomas and Helten, Holger and Bolm, Carsten}, title = {BN- and BO-Doped Inorganic-Organic Hybrid Polymers with Sulfoximine Core Units}, series = {Chemistry - A European Journal}, volume = {25}, journal = {Chemistry - A European Journal}, number = {55}, doi = {10.1002/chem.201903289}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-206194}, pages = {12708-12711}, year = {2019}, abstract = {While polysulfones constitute a class of well-established, highly valuable applied materials, knowledge about polymers based on the related sulfoximine group is very limited. We have employed functionalized diaryl sulfoximines and a p -phenylene bisborane as building blocks for unprecedented BN- and BO-doped alternating inorganic-organic hybrid copolymers. While the former were accessed by a facile silicon/boron exchange protocol, the synthesis of polymers with main-chain B-O linkages was achieved by salt elimination.}, language = {en} }